Cellulose succinate

Cellulose esters of aromatic acids, aUphatic acids containing more than four carbon atoms and aUphatic diacids are difficult and expensive to prepare because of the poor reactivity of the corresponding anhydrides with cellulose Httle commercial interest has been shown in these esters. Of notable exception, however, is the recent interest in the mixed esters of cellulose succinates, prepared by the sodium acetate catalyzed reaction of cellulose with succinic anhydride. The additional expense incurred in manufacturing succinate esters is compensated by the improved film properties observed in waterborne coatings (5). 

Liu CF, Sun RC, Zhang AP, Ren JL, Geng ZC. Structural and thermal characterization of sugarcane bagasse cellulose succinates prepared in ionic liquid. Polym Degrad Stab 2006 91 3040-3047. 

In many appHcations succinic acid and anhydride are esterified with polyhydric compounds, ie, polyols (57—59), cellulose (60), or starch (61—64). 

Mixed esters containing the dicarboxylate moiety, eg, cellulose acetate phthalate, are usually prepared from the partially hydroly2ed lower aUphatic acid ester of cellulose in acetic acid solvent by using the corresponding dicarboxyhc acid anhydride and a basic catalyst such as sodium acetate (41,42). Cellulose acetate succinate and cellulose acetate butyrate succinate are manufactured by similar methods as described in reference 43. 

Online detection using 4H nuclear magnetic resonance (NMR) is a detection mode that has become increasingly practical. In a recent application, cell culture supernatant was monitored on-line with 1-dimensional NMR for trehalose, P-D-pyranose, P-D-furanose, succinate, acetate and uridine.33 In stopped-flow mode, column fractions can also be analyzed by 2-D NMR. Reaction products of the preparation of the neuromuscular blocking compound atracurium besylate were separated on chiral HPLC and detected by 4H NMR.34 Ten isomeric peaks were separated on a cellulose-based phase and identified by online NMR in stopped-flow mode. 

Succinic acid is commonly produced in microbes because it exists as a part of the TCA cycle, one of the ordinary metabolic pathways for production of energy. Several groups in the world are developing this production system to produce cheaper succinic acid from renewable resources like starch, glucose, cellulose and so on. If succinic acid could be produced from cheap carbon sources and the price were competitive with the petroleum-base product, many C4 chemicals could be expected as derivatives. 1,4-Butanediol is the typical one, which has a huge market. 

The metabolism of anaerobic chytrids has not been studied in great detail, but it is known that most anaerobic chytrids studied so far produce formate, acetate, succinate, lactate and ethanol besides hydrogen and carbon dioxide when growing on cellulose, glucose or fructose as a carbon source (Julliand et al. 1998). Such a mixed acid fermentation is very similar to bacterial mixed acid fermentations that are, for example, well known for facultative anaerobic enteric bacteria, such as Escherichia coli. 

Propionic (propanoic) acid-producing bacteria are numerous in the digestive tract of ruminants. Within the rumen some bacteria digest cellulose to form glucose, which is then converted to lactate and other products. The propionic acid bacteria can convert either glucose or lactate into propionic and acetic acids which are absorbed into the bloodstream of the host. Usually some succinic acid is also formed. 

Inhibition Studies. A number of compounds were employed to study the amino acid residue(s) that are important for cellulase activity. Samples of enzyme (0.1 mL, 500 units) were pre-incubated with 0.1 mL of inhibitor in semimicroviscometers for 8 min at 35°C. CM-cellulose solution (0.8%, w/v), which had been separately equilibrated at 35°C for 20 min was added to the viscometers and initial viscosity losses were measured after 15 min. Inhibitors were replaced by buffer in control experiments. Compounds that are insoluble in buffer, e.g., N-ethylmalei-mide, diisopropyl fluorophosphate, and succinic anhydride, were dissolved in a small volume of 95% ethanol before assay. p-Chloromercuribenzoate (p-CMB) was first dissolved in 0.2M NaOH and the pH adjusted to eight prior to pre-incubation with cellulases. 

DMA Dimethylacetamide DMSO Dimethyl sulfoxide HPC-SL Hydroxypropyl cellulose, grade SL PBS Phosphate-buffered saline SLS Sodium lauryl sulfate TPQSTbcopheryl polyethylene glycol 1000 succinate. 

FIGURE 18.10 Inhibitory effect of polymers on recrystallization of nifedipine (NP) from a supersaturated solution at pH 6.8. HPMCAS, hydroxypropylmethyl cellulose acetate succinate HPMC, hydroxypropylmethyl cellulose HPMCP, hydroxypropylmethyl pthate PVP, polyvinyl pyrrolidone MAEA, methacrylic acid ethyl acrylate copolymer. (From Tanno, F., Y. Nishiyama, H. Kokubo, S. Obara. ZWMjDev Ind Pharm30 13. 

Jansen PJ, Kemp CA, Maple SR, Baertschi SW. Characterization of Impurities found by interaction of Duloxetine HC1 with enteric polymers hydroxy-propyl methyl cellulose acetate succinate and hydroxypropyl methylcellulose phthalaie. J Pharm Sci 1998 87(1) 81—85. 

Prior to high-performance liquid chromatography (HPFC), samples were filtered through a 0.2-gm pore size mixed cellulose ester filter (Schleicher Schuell, Dassel, Germany). Buffer components such as acetic acid, citric acid, maleic acid, and succinic acid were separated on an Aminex HPX-87H (Bio-Rad, Hercules, CA) organic acid column at 65°C using a... 

The analysis of aliphatic acids was performed using a P/ACE MDQ capillary electrophoresis instrument equipped with a 60 cm x 50 pm id fused silica capillary (Beckman Coulter, Fullerton, CA). The samples were filtered through a 0.45-gm cellulose acetate filter (Whatman, Maidstone, UK) prior to hydrodynamic injection at 15 psi for 4 s. The voltage was set to 20 kV at reversed polarity. The electrolyte, composed of 5.0 mM trimellitic acid, 50 mM tris(hydroxymethyl)-aminomethane, 1.0 mM tetradecyl-trimethylammoniumbromide, and 0.5 mM calcium chloride, had a pH of 9.8. Before use, it was filtered through a 0.2-gm cellulose nitrate filter and degassed withhelium. Detection was performedby indirect UV absorption at 220 nm. Succinic acid was used as internal standard. 

Figure 1. Postulated sizing reactions of (a) alkyl ketene dimers and (b) alkyl succinic anhydrides. R. and R are short alkyl chains. Cell-OH represents cellulose.

Magnesium stearate, stearic acid, sodium stearyl fumarate Hypromellose, hydroxypropyl cellulose, methylcellolose Ethylenediamine tetraacetic acid, butylated hydroxy toluene Sodium lauryl sulfate, Polysorbate 80 (Tween 80) Cyclodextrins, ethyl alcohol, propylene glycol D-a-Tocopheryl polyethylene glycol 1000 succinate, oleic acid... 

Cellulose acid phthalate, I, 320 Cellulose acid succinate, I, 320 Cellulose benzoate, I, 320 Cellulose carbamates, N-derivatives, I, 321... 

Cellulose acetate Cellulose acetate butyrate Cellulose acetate phthalate Cellulose acetate propionate Ethyl cellulose Hydroxyethyl cellulose Hydroxypropyl cellulose Hydroxyethylmethyl cellulose Hydroxypropylmethyl cellulose Hydroxypropylmethyl cellulose acetate succinate Hydroxypropylmethyl cellulose phthalate Methyl cellulose Na Carboxymethyl cellulose... 

Hydroxypropyl methylcellulose acetate succinate Hydoxypropyl methylcellulose phthalate Methyl cellulose... 

Water-soluble hydroxypropylmethyl cellulose and water-insoluble cellulose acetate are further treated with phthalic anhydride or succinic anhydride to yield hydroxypropyl methylcellulose phthalate, cellulose acetate phthalate, and hydroxypropyl-methylcellulose acetate succinate. These polymers are used as enteric materials and are water soluble or insoluble above or below a specific pH, respectively. 

Cellulose acetate, Plasticized cellulose triacetate, Cellulose acetate methyl carbamate, Cellulose acetate Ethyl- carbamate, Cellulose acetate phthalate, Cellulose acetate succinate... 

Formulation with Flydroxypropyl Cellulose Acetate Succinate (HPMCAS) ... 

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